Apparatus and method for developing an anatomic space for laparoscopic procedures

ABSTRACT

An improved laparoscopic apparatus for tunneling to a desired anatomical location and developing a surgical space is disclosed, including a tunneling member adapted to receive a laparoscope therein and an inflatable balloon secured on the tunneling member. The tunneling member has a passage extending between its open proximal and distal ends. A lip is integrally formed on the distal end to retain a laparoscope inserted into the passage, the lip having a substantially rounded and blunt distal edge. The lip defines a recessed or open center area in the distal opening, enhancing the field of view of the laparoscope therethrough. The balloon is formed from flexible, transparent material, and is rolled and secured to the tunneling member. The balloon includes inverted seams and/or unfused outer edges adapted to minimize tissue trauma during inflation, and has an extended distal portion adapted to be unrolled during space development, thereby improving distal space development and enhancing visualization of landmarks within the space being developed.

This is a Continuation application of application Ser. No. 08/857,193,filed on May 15, 1997, now U.S. Pat. No. 6,015,421.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus and method fordeveloping an anatomic space for laparoscopic procedures, and moreparticularly to an apparatus and method for providing laparoscopicvisualization during tunneling to a desired anatomic space as well asduring subsequent balloon inflation to develop the desired space.

BACKGROUND

A number of surgical devices may be used to develop a surgical spacewithin a body. For example, blunt dissectors or soft-tipped dissectorsmay be utilized to create a dissected space which is parallel to theplane in which the dissectors are introduced into the body.

More recently, surgical devices including an inflatable balloon havebeen used to develop an anatomic space. Such devices typically includean elongate shaft or obturator for tunneling into the body with theballoon attached to it. The balloon is generally collapsed initially,for example by gathering the balloon about the shaft, and is secured tothe shaft by a tubular sheath or cover. The tunneling shaft with thedeflated balloon thereon is introduced into the body and directed to adesired location. Once the desired location is reached, the balloon isdeployed by inflation to develop the anatomic space, generally causingdissection along a natural plane within the tissue structures.

The balloon generally comprises two similarly shaped panels that areheat sealed, sonic welded or otherwise substantially fused togetheralong their outer edges, creating a substantially fluid tight seamaround the balloon. Although the material comprising the balloon panelsis generally flexible, the material may become stiff and/or abrasivealong the seam. During tunneling or when the balloon is deployed, anexternal seam may move along the tissues in the anatomic space beingdeveloped, potentially causing tissue trauma, particularly in sensitivetissues, and/or resulting in undesired bleeding in the space.

More particularly, in relation to laparoscopic procedures, surgicaldevices have been developed that permit visualization during tunnelingas well as during development of the anatomic space. Such devicestypically include a tunneling shaft, an inflatable balloon, and alaparoscope. The tunneling shaft comprises a substantially rigid tubularmember having open proximal and distal ends, defining a passage adaptedto receive a laparoscope therein. The balloon is generally formed fromsubstantially transparent material, thereby allowing observation throughthe balloon wall. The distal end of the tunneling shaft may be insertedthrough a proximal end of the balloon into the interior of the balloon.Similar to other tunneling devices, the balloon is initially collapsedaround the tunneling shaft and may be covered by a sheath.

The distal end of the tunneling shaft generally includes a lip partiallyobstructing the open distal end. The lip may be formed by providing arounded tip on the distal end of the shaft and cutting away an angledsection of the tip, for example at a forty five degree angle. The lipprevents a laparoscope inserted into the tunneling shaft from extendingbeyond the distal end of the shaft.

During tunneling, a laparoscope inserted into the tunneling shaft may bepositioned for focus and used to observe the progress of the device, thetransparent balloon wall allowing observation through the open distalend of the tunneling shaft. Once the desired location is reached, theballoon is inflated. During inflation, the distal end of the tunnelingshaft and laparoscope may be moved around within the balloon to view thespace being developed, to observe tissue dissection, and to identifytissue structures.

One problem with such devices is that the lip on the tunneling shaft mayresult in a sharp distal edge. This sharp edge may contribute to tissuetrauma when the tunneling shaft is introduced into a body, and/or whenthe tunneling shaft is moved to observe the anatomic space beingdeveloped. The sharp edge may also damage or puncture the balloon,possibly requiring removal and replacement of the device.

In addition, the lip may substantially obstruct the field of view of thelaparoscope. Although the tunneling shaft often comprises substantiallytransparent material in order to transmit light, distortion through thewalls may impair peripheral visualization. Thus, the most effectivefield of view through the laparoscope is generally through the opendistal end of the tunneling shaft. Because the lip partially blocks thedistal end, however, the lip often obstructs the axial field of view.For this reason, such devices often employ an angled rather than astraight laparoscope, providing visualization at an angle out the opendistal end, rather than in an axial direction. Thus, to fully view thetissues being dissected, the tunneling shaft may have to be rotatedaxially, which may be disfavored in some procedures.

Accordingly, there is a need for an apparatus and method for developingan anatomic space which provides improved visualization during tunnelingand subsequent space development.

In addition, there is a need for a laparoscopic apparatus and method fordeveloping an anatomic space which substantially minimizes tissue traumaduring tunneling and development of the space, thereby reducing bleedingthat may obscure the field.

SUMMARY OF THE INVENTION

The present invention is directed to an apparatus and method forobserving tissue dissection while tunneling to a desired location withina body and for developing an anatomic space at the desired location.Generally, the apparatus includes a tunneling member and an inflatableballoon. The tunneling member comprises a substantially rigid tubularshaft having proximal and distal ends, having a passage extendingbetween the ends, and having an opening in the proximal end to receive aconventional laparoscope. The proximal end of the shaft may include ahandle thereon for directing the shaft during a procedure.

The distal end is generally truncated and includes an integrally formedlip. Preferably, the lip has a substantially rounded, blunt distal edge,adapted to minimize tissue trauma. In addition, the lip preferably is“U” shaped, partially defining an opening adjacent the axis of the shafthaving a recessed center in the opening, to enhance visualization andminimize obstruction of the field of view through the distal end.

The balloon generally comprises a substantially flexible, and preferablynon-elastomeric, material having an inflatable space therein, defining apredetermined shape capable of assuming collapsed and inflatedconditions. Preferably, the balloon has a substantially circular orelliptical shape, except for a bulge or extension in a distal portion ofthe balloon.

The balloon generally comprises two panels of material that are fused orwelded together around their periphery, creating a substantially fluidtight seam that defines the inflatable space of the balloon and providessubstantially flexible outer edges for the balloon. Preferably, flexibleouter edges are provided by fusing or welding the panels on theirperiphery, such as by heat sealing or sonic welding, to create a seam,turning the panels inside out, thereby creating an inverted seam whichextends slightly into the inflatable space in the balloon and areentrant outer profile at the seam on the balloon. Alternatively, theseam may be welded and set in by a predetermined margin from the outeredges of the panels. The balloon may also be selectively strengthened,by attaching or welding reinforcing panels to the walls of the balloon,such as in the distal portion of the balloon.

The balloon generally includes a proximal sleeve or neck having asealable opening therein, preferably having a handle with a boretherethrough that communicates with the inflatable space within theballoon. The distal end of the tunneling member may be directed into theinflatable space of the balloon through the bore in the handle, seals inthe handle providing a substantially fluid tight seal. Alternatively,the neck may be sealably attached directly to the outer wall of thetunneling member of the handle.

Prior to use, the tunneling member and balloon are generally assembled,and a conventional laparoscope or similar device is usually provided.Preferably, the balloon includes a bulge or extension in its distalportion, and the distal end of the tunneling member is inserted until itreaches, but does not enter, the distal portion of the balloon.Optionally, the distal end of the balloon may be reinforced by thickeror multiple sheets of balloon material suitably welded thereto.

The balloon is rolled, gathered or folded about the shaft of thetunneling member, or is provided pre-rolled, preferably as follows. Thebulge in the distal portion of the balloon is first rolled proximallyonto the anterior or top surface of the balloon. The sides of theballoon are then rolled laterally inward onto the posterior or bottomsurface of the balloon, until the balloon is substantially collapsedaround the shaft of the tunneling member. Alternatively, if the distalend of the tunneling member is directed to the outer edge of the distalportion of the balloon, the distal portion may not be rolled proximallybefore the sides are rolled laterally in. The balloon is then secured,preferably by a removable sheath or integral cover that substantiallyholds the balloon until the balloon is ready to be deployed. U.S. Pat.No. 5,540,711, the disclosure of which is incorporated herein byreference, describes sheaths and covers that may be used for embodimentsof a balloon in accordance with the present invention.

A laparoscope is generally inserted into the proximal end of thetunneling member, preferably until it engages the lip on the distal endof the shaft. The apparatus is then ready to be introduced into a body,for example between layers of the abdominal wall to create apreperitoneal space for laparoscopic hernia repair. For such aprocedure, an incision is made in the skin of a patient to access thedesired tissue layer, and the distal end of the tunneling member,together with the laparoscope and rolled balloon, is introduced into theincision. The tunneling member is advanced through the body tissue tothe desired location. Although the balloon covers the opening in thedistal end of the tunneling member, the substantially transparentmaterial of the balloon allows some observation of tissue duringadvancement of the tunneling member using the laparoscope.

Once the tunneling member reaches the desired location, the balloon isdeployed by removing the sheath or cover, thereby exposing the balloon.The balloon is then inflated by introducing fluid, such as salinesolution, through an inflation lumen into the inflatable space in theballoon (if an integral sheath is used to contain the balloon, inflationwill burst the sheath). This causes the balloon to expand, unrolling therolled portions, causing tissue dissection and developing the anatomicspace.

The method of preparing the collapsed balloon described above isparticularly useful in developing a preperitoneal space for laparoscopichernia repair. Prior to balloon inflation, the tunneling member ispreferably oriented such that the anterior surface of the balloon isdirected towards the posterior side of the pubis. As the balloon isinflated, the side portions unroll first, thereby substantiallyanchoring the balloon. The distal portion then unrolls, extending theanatomic space distally, allowing improved space development andexposure of anatomic landmarks.

In addition, as the digital portion unrolls, it engages the posteriorsurface of the pubis, abrading the surface to clear the field andenhance observation, particularly of Cooper's ligament. Cooper'sligament is a useful body structure for orienting the surgeon within thepreperitoneal space. Cooper's ligament has a substantially whiteappearance and may be more easily observed when free of other tissues,thus providing an important landmark within the space.

An additional feature of the apparatus of the present invention is theimproved seam of the balloon provided. During balloon inflation as theside portions and distal portion of the balloon unroll, the peripheraledges engage and move along tissues within the space. A balloon inaccordance with the present invention may have substantially less or nooutwardly protruding seam edges which might contribute to tissue traumaor bleeding and obstruction of the surgical field.

Accordingly, a principal object of the present invention is to providean improved apparatus and method for developing an anatomic space withina body that provides improved visualization and/or substantiallyminimizes tissue trauma during tunneling and subsequent spacedevelopment.

Other objects and features of the present invention will become apparentfrom consideration of the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of a laparoscopicapparatus in accordance with the present invention, with the balloonuncovered and unrolled.

FIG. 2A is a plan view of a distal end of a tunneling member for alaparoscopic apparatus in accordance with the present invention.

FIG. 2B is an end view of the distal end of the tunneling member shownin FIG. 2A.

FIG. 3A is a cross-sectional view taken along line 3—3 of FIG. 1,showing an external seam of the balloon prior to inverting the balloon.

FIG. 3B is a cross-sectional view taken along line 3—3 of FIG. 1,showing a preferred embodiment of the inverted seam of the balloon inaccordance with the present invention after inverting the balloon.

FIG. 3C is a perspective view of an adapter nipple for attaching aninflation lumen to a balloon in accordance with the present invention.

FIG. 3D is a cross-sectional view of an alternative embodiment of theperipheral seam of the balloon, with the outer edges engaging a tissuesurface.

FIG. 4 is a perspective view of a balloon for a laparoscopic apparatusin accordance with the present invention having reinforcing panelsattached thereto.

FIG. 5 is a cross-sectional view taken along line 5—5 of FIG. 4, showingthe reinforcing panels attached to the balloon.

FIG. 6 is a perspective view of a tunneling member with a laparoscopeinserted therein for a laparoscopic apparatus in accordance with thepresent invention.

FIG. 7 is a perspective view of a laparoscopic apparatus in accordancewith the present invention, showing the balloon covered by a removablesheath and having a laparoscope inserted into the assembled tunnelingmember.

FIG. 8 is a perspective view of the embodiment of FIG. 1, prior toinsertion of a laparoscope, with the balloon uncovered and unrolled.

FIG. 9 is a perspective view of another preferred embodiment of alaparoscopic apparatus in accordance with the present invention, withthe balloon uncovered and unrolled.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning to the drawings, FIG. 1 shows a preferred embodiment of alaparoscopic apparatus 10 in accordance with the present invention. Theapparatus 10 includes a tunneling member 20, and an inflatable balloon40. The tunneling member 20, which may be formed from a suitable medicalgrade plastic, such as polycarbonate, comprises an obturator shaft 22and a handle 38. The obturator shaft 22 is sufficiently rigid to permittunneling through tissue layers within the human body. The shaft 22 hasan open proximal end 24, an open distal end 26, and a passage 28extending between the proximal end 24 and the distal end 26 adapted toreceive a conventional laparoscope 60 therein. The handle 38 is attachedto the proximal end 24 of the shaft 22, thereby allowing a surgeon tograsp and manipulate the shaft 20 during performance of a procedure. Thehandle 38 preferably includes a bore (not shown) therethrough thatcommunicates with the passage 28 in the shaft 20, and includes fluidseals (not shown) therein allowing the laparoscope 60 to be sealablyinserted into the passage 28 and allowing balloon inflation.

The distal end 26 includes an integrally formed retaining lip 30 forcontaining the laparoscope 60 inserted into the tunneling member 20, andpreventing the laparoscope 60 from extending beyond the distal end 26.Generally, the lip 30 has a substantially rounded, blunt distal edge 34,as shown in FIGS. 2A and 2B. Preferably, the lip 30 extends radiallyinward from the perimeter of the tunneling member 20 around the distalend 26, thereby defining a substantially “U” shaped distal edge 34. Thedistal edge 34 of the lip 30 defines a recessed or open center area 36in the opening 32, thereby substantially minimizing obstruction of theopening 32, and enhancing the field of view axially through the distalend 24, as explained below.

Referring once gain to FIG. 1, the balloon 40 generally comprises asubstantially round or elliptical shaped body having an inflatable space58 therein, and including side portions 46 and a bulge or extension in adistal portion 48 of the balloon 40. The balloon 40 is generally formedfrom substantially flexible sheet material, preferably a suitablenon-elastomeric medical-grade material such as polyvinyl chloride orpolyurethane. The balloon 40 thus preferably defines a predeterminedshape capable of assuming collapsed and inflated conditions. Inaddition, the material is preferably substantially transparent, therebyallowing visualization through the walls of the balloon 40.

The balloon 40 is generally formed from two sheets or panels 52 ofmaterial, preferably defining anterior and posterior surfaces of theflat balloon 40. The panels 52 are fused or welded together around theperiphery, creating a substantially fluid tight seam 56 that defines theinflatable space 58 in the balloon 40. Preferably, the seam 56 is heatsealed or sonic welded at the periphery as shown in FIG. 3A. Because theouter edges 54 of the peripheral seam 56 may be rough or sharp and maycause tissue trauma during use of the balloon, the seam 56 is preferablyinverted or substantially contained within the inflatable space 58 inthe balloon 40, as shown in FIG. 3B. This may be achieved by welding theperiphery of the panels 52 to create a seam 56, turning the panels 52inside out, and compressing the panels 52 together, thereby providingreentrant or partially reentrant outer edges 54 around the periphery ofthe balloon 40. The reentrant edges 54 around the periphery of thefinished balloon 40 provide a substantially smooth profile that contactsthe tissues atraumatically when the balloon 40 is inflated to developthe space. The balloon 40 may be fabricated in a manner such that partor all of the peripheral seam 56 is inverted. Alternatively, theperipheral trim 55 after welding or bonding may be extended beyond theweld periphery of the seam 56 to assure that the edges 54 will fold flatagainst the balloon surface 52 when in contact with tissue duringinflation, as shown in FIG. 3D. In most instances, a margin of about 1mm for the periphery trim 55 should be adequate, but may vary with theballoon materials employed.

The balloon 40 is generally provided with a proximal sleeve or neck 42into which the shaft 22 of the tunneling member 20 is inserted. As shownin FIG. 1, the neck 42 includes a handle 43 which includes a sealablebore (not shown) therethrough, although alternatively the neck 42 may beattached directly to the shaft 22, as shown in FIG. 9. The handle 43 mayinclude an inflation port (not shown) in communication with the neck 42,allowing a suitable inflation medium, such as saline solution, to beintroduced through the neck 42 into the inflatable space 58 of theballoon 40 for inflating the balloon 40.

Alternatively, as shown in FIG. 1, the balloon 40 may instead include aninflation lumen 70 in communication with the inflatable space 58 of theballoon 40. A flexible hollow tube 74 with an open distal end isinserted into an inflation lumen extension 72 on the balloon 40 andsecured in a fluid tight manner thereto. The proximal end of theflexible tube 74 is secured to a conventional wye adapter 76 includingan inflation fitting 77 and an evacuation fitting 78. Alternatively, insome instances, as with a tissue expander, the balloon may not include aproximal sleeve or handle (not shown), only a fill lumen and aninjection port. The seam may then extend substantially entirely aroundthe periphery of the balloon and may be provided inverted or with amargin as described above.

The inflation lumen 70 is generally provided as shown in FIG. 1 when theballoon edges 54 are not inverted at the point where the inflation lumenextension 72 is placed on the balloon 40. This configuration would beappropriate when none of the periphery of the balloon 40 is inverted, orwhen part of the periphery of the balloon 40 is welded (e.g. along thedistal 48 and side portions 46), the welded portions are inverted, andthe balance of the periphery of the balloon 40 (e.g. the portionincluding the inflation lumen extension 72) is then welded, the balanceof the periphery thus remaining uninverted.

In embodiments where an entirely inverted periphery is desired, such asa tissue expander, the inflation lumen may be moved from the peripheralseam 56 of the balloon 40 onto one of the two balloon panels 52 fromwhich the balloon 40 is formed (not shown). In such an embodiment, anadapter nipple 172 may be formed as shown in FIG. 3C. A flange 173 ofthe adapter nipple 172 is welded or bonded around a hole (not shown)formed in the desired balloon panel. After peripheral welding of theballoon seam, the balloon may be inverted through the nipple 172 and aninflation tube (not shown) may be bonded or welded to the neck 174 ofthe nipple 172 by any suitable means. The resulting balloon is totallyenclosed with an attached inflation lumen and no protruding seam edges.Alternatively, when welding or bonding the adapter nipple 172 onto theballoon, the balloon may be inverted and partially inflated, theinflation thus resisting the pressure of the welding or bonding fixture.Using these methods, or variations of them, balloons may be provided ofvarious shapes and construction with predetermined amounts of exposedand/or inverted seams.

In addition to the panels 52 defining the walls of the balloon 40, theballoon 40 may be selectively strengthened using one or more reinforcingpanels of material similar to that used for the walls of the balloon 40.For example, as shown in FIG. 4, one or more additional panels 59 may beincluded in the distal portion 48 of the balloon 40 to enhance thepuncture-resistance of the distal portion 48, that is, to substantiallyminimize the risk of stretching or tearing the balloon 40. Suchreinforcing panels may be attached to the walls of the balloon 40 byconventional adhesives and/or may be welded to the balloon 40. Forexample, FIG. 5 shows reinforcing panels 59 being fused in the seam 56on the periphery of the balloon 40. Preferably, the panels 59 are alsoadhered to the inside surface of the adjacent panel 52 using welding oradhesives. If the balloon 40 is to be inverted, the reinforcing panels59 may be fastened to the outside surface and then the balloon 40 may beinverted.

Turning now to FIG. 8, when assembled into a complete apparatus 10, theobturator shaft 22 of the tunneling member 20 passes through the handle43 and the neck 42 into the inflatable space 58 of the balloon 40. Thedistal end 26 of the shaft 22 extends through the balloon 40 to thedistal portion 48 thereof, which may be reinforced as shown. Preferably,the distal end 26 does not extend into the distal portion 48, therebyallowing the distal portion 48 to be rolled, as described below.Alternatively, the distal end 26 may extend through the distal portion48 until it presses against the nipple 44 in the balloon 40.

Preferably, the balloon 40 is wrapped and secured directly onto theobturator shaft 22 after the tunneling member 20 has been inserted intothe balloon 40, allowing the balloon 40 to be fastened tightly thereto.The obturator shaft 22 is inserted into the flat balloon 40 until thedistal end 26 reaches but does not enter the extension in the distalportion 48. The distal portion 48 of the balloon 40 is then rolledproximally along the anterior or top surface of the balloon 40, untilthe balloon 40 engages the distal end 26 of the tunneling member 20.Alternatively, the distal end 26 of the tunneling member 20 may bedirected against the nipple 44 on the distal portion 48 of the balloon40, whereupon the distal portion 48 is not rolled. The side portions 46of the balloon 40 are then rolled laterally in, preferably along theposterior or bottom surface of the balloon 40, until the bottom 40 issubstantially collapsed around the shaft 22 of the tunneling member 20.

The balloon 40 is then secured, preferably by an integral cover 80 thatincludes a weakened axial seam 82, as shown in FIG. 7. Alternatively,the balloon 40 may be covered with a removable sheath (not shown) thatmay be withdrawn proximally along the apparatus 10 after the apparatusis delivered to a desired location in a body. In either case, the coversubstantially holds the balloon 40 until the time of deployment.

Turning to FIGS. 1, 6 and 7, a conventional laparoscope 60 is shownafter it has been fully inserted into the apparatus 10. The laparoscope60 includes a shaft 62 that is inserted into the bore in the handle 38of the tunneling member 20, preferably until a distal end 66 of thelaparoscope shaft 62 engages the lip 30 on the distal end 26 of theshaft 22, as shown in FIG. 6. The lip 30 thus prevents furtheradvancement of the laparoscope shaft 62, and retains the distal end 66of the laparoscope shaft 62 within the obturator shaft 22. Thelaparoscope 60 includes a fiber optic light port 64 to provideillumination to the lens (not shown) on the distal end 66 of thelaparoscope shaft 62. Although an angled scope may be used, the improvedlip 30 on the tunneling member 20 enhances the field of view axiallythrough the distal end 26, allowing a straight scope to be used moreeffectively during tunneling, as described below.

The apparatus 10 may then be introduced into a body, for example, tocreate a preperitoneal space to permit laparoscopic hernia repair. Anincision is made in the skin of a patient, and the distal end 26 end ofthe tunneling member 20, covered by the rolled balloon 40, is introducedbetween desired tissue layers. The tunneling member 20 is advanced alongwith the rolled balloon 40 and the laparoscope 60 through the body to adesired location therein. Although the balloon 40 covers the opening 32in the distal end of the tunneling member 20, its substantiallytransparent walls do not obstruct substantially light transmission orvisualization therethrough. Thus, during tissue dissection from theadvancement of the tunneling member, the laparoscope 60 allowscontinuous monitoring of the progress of the apparatus 10 to the desiredlocation.

Once the tunneling member 20 reaches the desired location, preferablythe desired preperitoneal location, the balloon 40 is deployed.Preferably, the balloon 40 is inflated, causing the weakened seam 82 onthe cover 80 to tear, thereby exposing the balloon 40 within the space.Alternatively, if a sheath (not shown) is used, the sheath is withdrawnby pulling it proximally over the tunneling member 20 and out theincision. The balloon 40 is then inflated by introducing fluid, such assaline solution, through the inflation lumen 74 into the inflatablespace 58 in the balloon 40. This causes the balloon 40 to expand,unrolling the rolled portions, causing tissue dissection and developingthe anatomic space.

The method of preparing the collapsed balloon 40 described above isparticularly useful in developing a preperitoneal space for laparoscopichernia repair. Preferably, prior to inflating the balloon 40, thetunneling member 20 is oriented such that the anterior surface of theballoon 40 is directed towards the posterior side of the pubis. As theballoon 40 is inflated, the sides 46 unroll prior to the distal portion48, thus substantially anchoring the balloon 40 within the space.Thereafter, as the distal portion 48 unrolls, it engages the posteriorsurface of the pubis space, clearing the distal field, and thus enablingimproved observation of Cooper's ligament in the space being developed.

The unrolling action of the distal portion 48 is particularly useful forlaparoscopic hernia procedures. First, if the tunneling member 20 is notinserted as deeply behind the pubis as desired, the distal portion 48extends the space being developed distally. In addition, the unrollingof the distal portion along the posterior surface of the pubis enhancesvisualization of Cooper's ligament. Cooper's ligament, which has asubstantially white appearance, is a particularly useful landmarkstructure located on the posterior surface of the pubis, thus improvinga surgeon's orientation within the space.

Referring once again to FIGS. 3A and 3B, the improved outer edges 54 andseam 56 of the balloon 40 in accordance with the present invention alsosubstantially enhance visualization during space development. When theballoon 40 is inflated, the sides 46 and the distal portion 48 of theballoon 40 unroll, moving the outer edges 54 along tissue surfaces ofthe space being developed. Because the peripheral seam 56 is inverted,the reentrant outer seam profile of the balloon 40 is substantiallysmooth and flexible in its contact with tissue and moves along thetissue surfaces with minimal scratching or tearing, minimizing bleeding.Particularly when the distal portion 48 is unrolled in the preperitonealspace, minimized bleeding is important for improving visualization.

Another important feature of the apparatus 10 in accordance with thepresent invention is the lip 30 on the tunneling member 20, and therecessed area 36 defined by the lip 30. Referring to FIGS. 2A and 2B,during tunneling dissection, the lip 30 provides a substantiallyrounded, blunt distal edge 34, that allows the distal end 26 of thetunneling member 20 to advance through body tissues with minimizedtissue trauma. In addition, the blunt distal edge 34 substantiallyreduces the risk of puncturing or tearing the balloon 40 when thetunneling member 20 is advanced through the body and/or when thetunneling member 20 is moved during inflation of the balloon 40 tovisualize the space being developed.

In addition, the lip 30 defines an open center area 36 in the opening 32that substantially enhances the axial field of view through the distalend 26 of the tunneling member 20. This allows a straight scope to beused more effectively to view axially out the distal end 26 of thetunneling member 20.

While the invention is susceptible to various modifications, andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is not to be limited to the particular formsor methods disclosed, but to the contrary, the invention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the appended claims.

What is claimed is:
 1. A laparoscopic apparatus for creating ananatomical working space between tissue layers in a body, said apparatuscomprising: a tunneling member comprising a substantially rigid shafthaving open proximal and distal ends, and having a passage extendingtherethrough between said proximal and distal ends, said passage beingadapted to receive a laparoscope therein, said distal end including aninward extending lip thereon configured for retaining the laparoscopefrom extending beyond said distal end and enhancing a field of viewthrough said distal end; and a balloon having an inflatable space andbeing capable of assuming collapsed and inflated conditions, saidballoon having a proximal sleeve for receiving said distal end of saidtunneling member therein.
 2. The apparatus of claim 1, wherein said lipcomprises a substantially blunt distal end on said tunneling member. 3.The apparatus of claim 1, wherein said lip extends radially inward froma perimeter of said distal end, said lip thereby defining a recessedarea in an opening in said distal end, said recessed area being adaptedto enhance said field of view axially through said distal end.
 4. Theapparatus of claim 1, wherein said lip comprises a rounded substantiallyblunt distal end of said tunneling member, said lip being adapted tosubstantially minimize tissue trauma when said tunneling member isadvanced through tissues in the body.
 5. The apparatus of claim 1,wherein said balloon comprises two panels substantially fused togetheralong a seam thereby defining said inflatable space, said seam extendingaround a periphery of said panels and being set in from outer edges ofsaid panels.
 6. The apparatus of claim 5, wherein said seam comprises aheat seal.
 7. The apparatus of claim 5, wherein said outer edges of saidpanels define unfused outer edges of said balloon.
 8. The apparatus ofclaim 1, wherein said balloon comprises two panels substantially fusedtogether along a seam thereby defining said inflatable space, said seambeing at least partially inverted into said inflatable space, said seamthereby having at least a partially reentrant outer profile.
 9. Theapparatus of claim 1, wherein said balloon includes an extended distalportion, said distal portion being adapted to be rolled proximally alonga surface of said balloon, thereby at least partially defining saidcollapsed condition.
 10. The apparatus of claim 1, wherein said balloonincludes a reinforcing panel on a portion of said balloon, saidreinforcing panel comprising a substantially transparent, flexiblematerial, said reinforcing panel being adapted to enhance apuncture-resistance characteristic of said portion.
 11. The apparatus ofclaim 10, wherein said balloon includes a distal portion, saidreinforcing panel extending proximally from an outer seam of said distalportion.
 12. The apparatus of claim 11, wherein said reinforcing panelextends proximally along an inside surface of said distal portion. 13.The apparatus of claim 10, wherein said material of said reinforcingpanel is of the same material as said balloon.
 14. An inflatable balloonfor creating an anatomical working space between tissue layers in abody, comprising: two panels substantially fused together along a seamextending around a periphery of the panels, thereby defining aninflatable space within the panels; and an adapter nipple attached toone of the panels and communicating with the inflatable space forinflating and deflating the balloon between inflated and collapsedconditions.
 15. The inflatable balloon of claim 14, further comprisingan inflation tube attached to a neck of the adapter nipple.
 16. Theinflatable balloon of claim 14, wherein the seam is at least partiallyinverted into the inflatable space, the balloon thereby having at leastpartially reentrant outer edges.
 17. The inflatable balloon of claim 16,wherein the seam is substantially entirely inverted around the peripheryof the panels.
 18. A method for forming an inflatable balloon forcreating an anatomical working space between tissue layers in a body,the method comprising: fusing two panels together along a seam extendingaround a periphery of the panels, thereby defining an inflatable spacewithin the panels; forming a hold in one of the panels; and attaching anadapter nipple to one of the panels around the hold, the adapter nipplecommunicating with the inflatable space for inflating and deflating theballoon between the inflated and collapsed conditions.
 19. The method ofclaim 18, further comprising attaching an inflation tube to a neck ofthe adapter nipple.
 20. The method of claim 18, further comprisingturning the panels inside out such that the seam is at least partiallyinverted into the inflatable space, the balloon thereby having at leastpartially reentrant outer edges.
 21. The method of claim 20, wherein theadapter nipple is attached to one of the panels before the panels arefused together, and wherein the panels are turned inside out through theadapter nipple.
 22. The method of claim 20, wherein the adapter nippleis attached to one of the panels after the panels are fused together,and wherein the balloon is at least partially inflated before attachingthe adapter nipple.
 23. The method of claim 18, wherein the adapternipple is attached to one of the panels by welding or bonding.